Hi Benja,
> You can find MaybeT here:
>>http://www.haskell.org/haskellwiki/New_monads/MaybeT
Thank you, that you spent some time figuring this out. This is exacly
what I have expected. (This "print" was debug leftovers).
Now I will try to understand how exacly this works.
My big thanks to you again,
Radek.